【Mybatis Plus-03】分页查询

@EnableTransactionManagement
@Configuration
@MapperScan("com.cy.springboot.mapper")
public class MybatisPlusConfig {

    // 分页插件
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        //构建拦截器对象
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        // 添加分页拦截器，并指定数据库类型为MySQL
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        // 返回拦截器对象
        return interceptor;
    }
}

自定义异常值
Constants

public interface Constants {
    String CODE_200 = "200"; //成功
    String CODE_401 = "401"; //权限不足
    String CODE_400 = "400"; //参数错误
    String CODE_500 = "500"; //系统错误
    String CODE_600 = "600"; //其他业务错误
}

接口数据返回类
Result.java

@Data //getter/setter
@AllArgsConstructor //无参构造
@NoArgsConstructor	//有参构造
public class Result {
    private String code;
    private String msg;
    private Object data;

    public static Result success() {
        return new Result(Constants.CODE_200, "", null);
    }

    public static Result success(Object data) {
        return new Result(Constants.CODE_200, "", data);
    }

    public static Result error(String code, String msg) {
        return new Result(code, msg, null);
    }

    public static Result error() {
        return new Result(Constants.CODE_500, "系统错误", null);
    }
}

UserController.java

@RestController
@RequestMapping("/user")
public class UserController {
		//分页查询
	    @GetMapping("/page")
   		public Result findPage() {
	        Page userPage = new Page<>(); //Page需指定实体类对象
	        userPage.setCurrent(1); //设置当前页
	        userPage.setSize(1); //设置每页多少条数据
	        Page page = userService.page(userPage); //调用userService.page()方法，传入userPage，返回Page对象
	        return Result.success(page);
    }

接口测试

打印sql

@RestController
@RequestMapping("/user")
public class UserController {
	//分页查询
	@GetMapping("/page")
    public Result findPage(@RequestParam Integer pageNum,
                           @RequestParam Integer pageSize) {
        QueryWrapper queryWrapper = new QueryWrapper<>(); //通过QueryWrapper构造器，指定构造对象
        queryWrapper.orderByDesc("id");//使用wrapper的条件构造器
        return Result.success(userService.page(new Page<>(pageNum, pageSize), queryWrapper));//wrapper可以丢到userService.page()方法中
    }
}

接口测试，
http://localhost:8081/user/page?pageNum=1&pageSize=1
query中需要指定pageNum和pageSize(当前页，每页数据条数)
打印sql